The invention relates to an apparatus for opening compressed fiber bales, e.g. of cotton, synthetic fibers, etc., by a reducing device which is adjustable in height for guiding it over the surface of the compressed bale or row of compressed bales to be worked, the distance to be maintained over the bale surface or the advance of the removing device being controlled by a scanning means.
The adjustment in height of the reducing device with respect to the surface of the compressed bale to be worked is realized in different ways. It is, for example, possible to scan the height of the set up bales by manual adjustment. The corresponding height value is stored in a microcomputer, and the automatic setting of the predetermined depth of removal is controlled individually per group of bales in case of each reducing pass.
Further, it has been known to use as scanning means individual rods of the grid through which operate milling disks of a milling roller and which rests on the compressed bale surface to be reduced, so that, upon a contact of the scanning rod with the surface of the bale, the lowering movement of the reducing device is stopped, whereupon its operational advance may be performed.
According to another embodiment, the bale height is scanned by sensors which are disposed outside the reducing device and more or less at the underside of the reducer housing. The sensors scan the distance of the reducer housing from the bale surface to be removed. If the reducing device has reached the bale surface, the lowering advance thereof is stopped by respective control means.
It is very seldom that the surface to be worked of the set up compressed bale or of the bales is a plane, or of even height, but usually, it is considerably varying in height, in particular, if the pressure from the banded bales is released. Subject to the intensity of the precedingly exerted pressure, the aspect of the top surface of the bales is different, and this is also true for the situation inside the bale surface. In case of the known scanning means used for scanning the height of the bale surface under treatment, mis-scanning by the influence of a so-called apparent height of the bale surface to be worked cannot be excluded.